Insulated glazing units (“IGU”), as that term is used herein, means two or more layers of glass, which are sometimes called glass lite panels, separated by a spacer frame along the edge and sealed to create a dead air (or other gas, e.g., argon, nitrogen, krypton) space between the layers. The spacer frame includes spacers, which are conventionally hollow tubes, also called spacer tubes, of a conductive material, such as but not limited to aluminum or steel, but which may not be hollow in some instances and which may be made of polymeric materials. The spacer frame, in some instances, may include a spacer key, which is sometimes called a spacer connector, that is inserted into ends of spacers to bridge the ends together. The spacer keys conventionally have the same outer profile as the ends of the spacers and may be hollow or solid like the corresponding spacers with which they interface. Active glazings, which form a part of the IGU and which include electrochromic glazings, may be applied or deposited to one of the glass lite panels. An electrochromic glazing, may have a laminate structure (see copending U.S. Patent Application Publication Nos. 2011/0261429 A1 and 2011/0267672 A1 and copending U.S. patent application Ser. Nos. 13/906,456 and 13/906,487, the disclosures of which are hereby incorporated by reference herein in their entireties). For example, the electrochromic glazings may include a series of thin films that are applied or deposited to one of the glass lite panels. Electrochromic glazings or coatings include electrochromic materials that are known to change their optical properties in response to the application of an electric potential which can create coloration or tinting within the electrochromic glazings. Common uses for these glazings include architectural windows, as well as windshields and mirrors of automobiles. Further details regarding the formation of IGUs can be found in, for example, U.S. Pat. Nos. 7,372,610 and 7,593,154, the entire disclosures of which are hereby incorporated by reference herein in their entireties.
As known to those of ordinary skill in the art, electrically conductive busbars are typically applied along the surface of one of the glass lite panels such that upon assembly of an IGU, the busbars are either outside an IGU spacer/polyisobutylene (“PIB”) seal, or “spacer seal” as that term is used herein, forming an IGU thermal break cavity or mainly inside the spacer seal. For example, as shown in FIG. 1, an IGU 1 may have a glass panel 2 on which a busbar 3 is applied such that the busbar 3 is mainly within a perimeter defined by sides of a spacer 5 and a spacer seal 4 placed between the spacer 5 and the glass panel 2 having approximately the same perimeter as the spacer 5. As shown, in such a configuration, the busbar 3 must be applied to extend under the spacer seal 4 to a region outside the perimeters of the spacer seal 4 and the spacer 5 to allow for the formation of a busbar solder tab 7 on an end of the busbar 3 that provides a contact area to which a wire 9 can be soldered to provide a sufficient solder joint 8 for a consistent electrical connection. The busbar solder tab 7 must be placed such that there is sufficient clearance between the solder joint 8 and the spacer 5 to prevent electrical shorting due to undesired contact between the spacer 5 and the solder joint 8 during the assembly process or during slight movements that may occur over the useful life of the IGU. In addition, sufficient clearance is needed to provide space for a solder gun tip to land and create a solder joint and, in some instances, to permit the addition of a sealant onto the busbar and busbar solder tab after soldering to either or both prevent solder tab corrosion and prevent argon or other inert gases from exiting a cavity of the IGU defined by the spacer 5 and the spacer seal 4 as well as the spacer seal 14 opposing the spacing seal 4.
To provide sufficient clearance, the spacer 5 has been dimensioned to have a smaller perimeter than IGUs that do not require electrical connectivity. However, in certain architectural frame configurations, one or both of the smaller perimeter spacer and corresponding spacer seal is visible within the viewable area of the frame unless an obscuration mask is applied, such as described in U.S. patent application Ser. No. 13/797,610, the entire disclosure of which is hereby incorporated by reference herein, which may be used to improve the aesthetic look of such an architectural glazing frame system but which may add cost while still causing a reduction in the viewable area of the frame as compared to IGUs not requiring electrical connectivity.
Thus, there exists a need for an electrical interconnection to busbars in an IGU cavity without requiring a reduction in the perimeter of a spacer to accommodate for such a connection.